1. Field of the Invention
This invention relates to an ink jet printer and more particularly to an electrostatic deflecting ink jet printer using inflammable ink.
2. Description of the Prior Art
The ink used with an ink jet printer is required to have characteristics suitable for formation and control of ink droplets and, in addition, a high ability to attach to the recording surface, to dry immediately after recording and to resist the weather for a long period of time after recording. Especially, a high ability to attach, dry and resist the weather is required in the case where the recording surface is made of a metal or plastics. Generally, such characteristics are attained by using an inflammable ink with a solvent including alcohol such as ethyl alcohol. In the ink jet printer using inflammable ink, part of the ink emitted from a nozzle toward the recording surface is vaporized. Deflecting plates impressed with a high voltage are located downstream of the nozzle in order to deflect the ink droplets. The deflecting plates, if ink, dust or like is attached thereto, are likely to generate a spark discharge. If a spark discharge is generated for this reason or other, the vaporized inflammable ink is liable to burn.
The technique of coating a thin insulating material on the deflecting plates in order to prevent spark discharge is already disclosed by J. W. Haskell, M. P. Marcus and D. A. Walker "Deflecting Plate Assembly for Multiple Ink Jet Printer", I.B.M Technical Disclosure Bulletin, Vol. 12, No. 11, April 1970. The coating of the deflecting plates, however, has the disadvantages of complicating the construction on the one hand and reducing the potential of the deflecting plates on the other hand.